High-tech elliptical workout machines stand out from the rest

Buying an expensive, all-body elliptical machine -- even cutting-edge models that push the technology envelope like the novel sit-down and multi-mode models tested here -- might seem a bit counterintuitive in the midst of tough economic times. But bull and bear markets don't matter if you think of health as a long-term investment. The four excellent, club-quality machines below, each of which deliver smooth, heart-rate-monitored, arm-and-leg aerobic workouts that burn calories without joint stress, will pay dividends for decades.

Change it up

Precor AMT (Adaptive Motion Trainer): Unlike other ellipticals on the market, it features a free-form, user-determined foot motion that can, on the fly, change from a vertical stepping motion to an all-out, full-stride running motion.

Likes: Exhilarating, effective and addictive. I loved the variety and challenge; it can be a different workout every day -- or every minute. Allowing you to move the way you want, from easy to all out, it encourages a harder workout than a normal elliptical. The stride length automatically varies from zero to 27 inches, as you step, stride, run, walk or anything in between. Includes resistance adjustment, heart-rate programs and a variety of workout programs but no elevation controls, only a lighted "interactive stride length" dial that lets you watch and experiment with your own real-time motion. Relatively floor-space-friendly at 56 inches long.

Likes: Although originally intended for older people, it provides a superb workout for all ages. The comfortable seating position calls to mind a new and improved recumbent bike, with the short seat and back pad gliding up and back at a 45-degree angle. The back pad also tilts for a custom fit. Great variety; programs allow all-body, arms-only and legs-only workouts. Multi-position handlebar lets you work arms at different angles.

Dislikes: Poor control-panel placement. Although I'm of average height (just over 5-foot-9) I had to reach forward, off the back pad, to press the resistance and workout keys. While merely irritating for me, it would be harder to manage for short, senior exercisers. A land yacht at 71 inches.

Likes: Super-smooth, solid feel even when you're going all out. The stride length automatically lengthens from 20 to 23 inches as you speed up or increase the incline, so you can simulate a hands-free, near-running motion. It has a natural elliptical footpath, with footpads that have less of a forward and backward tilt than other brands. Includes narrow-spaced (and therefore natural) foot placement, a variety of heart-rate programs and the highly challenging and effective Sprint 8 anaerobic interval program. Just 57 inches long.

Dislikes: Poor panel-control placement. When pressing "up" and "down" keys, I had to thread my fingers carefully through obstacles such as the heart-rate grip bars and a water bottle.

PaceMaster Silver XT: Conventional-looking elliptical with an unconventional feel and programming at a price that's a relative bargain.

Likes: Great deal. As rock solid and smooth at full speed as a $5,000 machine. The company attributes that to a double-strut drive system that separates the footpads from the motor-drive system. Very good pedigree -- this is the first exercise machine that is not a treadmill from PaceMaster, a highly regarded manufacturer known for high quality at a moderate price. Twelve programs include a unique heart-rate-control mode that adjusts resistance to keep you in the same heart-rate zone. Includes double water-bottle holders and a handy, nonslip iPod tray.

Dislikes: Does not offer elevation change. Eats up lots of real estate at 79 inches long.